Ute_Man wrote:Are these the injector drivers on the MS3x?
UnaClocker wrote:You can put a diode on a relay to help clamp the flyback, could you do the same at the injectors? Might not be the desired long term solution, but seems like it'd get rid of that 39v spike. Think a 1n4001 would do the trick, or would it need to be stronger/faster than that?
UnaClocker wrote:Interesting. So if it didn't clamp them at all, they'd close even faster? Allow the voltage to go up to whatever it wants?
Ute_Man wrote:Could injectors be driven with IGBT's? Those things seem a lot more robust than MOSFETs, they take some pretty wicked flyback from the coils from time to time. (Sorry if I'm going off on a tangent here, always trying to expand my knowledge)
EFIDART512 wrote:I just scoped mine to look at the active clamp (internal to the device) to have a look. It clamps right at 39 volts.
If the internal clamp failed, then the device could/would get killed by the fly-back pulse from the injector coil. A secondary clamp in addition would provide protection if the active clamp died. Mine isn't running on the car yet but I imagine that a stuck ON injector isn't a good thing.
Attached is a pic of the working vnd5n07 if anyone is interested.
SymTech Laboratories wrote:No one is sure that the flyback is what's damaging these VND5N07's anyway.
subwoofer wrote:Launching a theory here: Although the VND is internally ESD protected there are limits to how much they can take. Is there some common point in time and/or space all the failed components share? Could they have been mishandled somewhere before installation?
Keithg wrote:I found mine when I probed the gate. The fet driver, IXDN404, was not able to drive the gate any more. My schematic has a pull down resistor on the gate and a resistor inline to the gate from the fet driver. When it failed, I was in 3rd gear going about 15 mph. I pressed on the accelerator and then it was running on 3 cylinders. So, the PW was low then went high when they failed. Mine failed and never came back. These are Bosch -431 HiZ injectors.
Peter Florance wrote:Can you measure the gate to source resistance of the dead device?
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